Junk Volume: Why Half Your Sets Might Be Wasted (And How to Tell)

Junk volume is any set too far from failure (or too fatiguing to recover from) to add meaningful muscle stimulus. If your sets stop five or six reps shy of failure, you're paying the time, joint wear, and recovery cost of training without collecting the growth. Survey data cited by Jeff Nippard suggests roughly half of self-directed sets land here — and most lifters have no idea, because we're terrible at judging our own effort.

I've coached people who train four days a week, never miss a session, and barely grow. Almost always the problem isn't their split or their protein. It's that their "hard" sets aren't hard. They count the sets. The sets don't count back.

Let me unpack what junk volume actually is, why the final reps are the only ones that matter, and how to fix it without just doing more.

What is junk volume?

Junk volume is training volume that costs you time, energy, and recovery capacity without producing a proportional gain in muscle or strength. It comes in two flavors. The first — and more common — is sets stopped too far from failure to recruit and fatigue the muscle. The second is excessive sets: piling on volume past the point where each added set still pays off.

Most people assume junk volume means doing too many sets. It usually means the opposite — doing easy sets. A five-set workout can be almost entirely junk if every set ends at five-plus reps in reserve. Quantity isn't the issue. Intensity of effort is.

How do you know if a set is junk volume?

A set is junk volume if you ended it with more than about 3 reps left in the tank, used a near-trivial load, or pushed so deep into fatigue that it wrecks your next session. The practical test: could you have done four or five more clean reps? If yes, that set probably delivered close to zero stimulating reps, even though it counted on your training log.

Here's the catch — you're a bad judge of this. Lifters chronically overestimate how close to failure they are. They feel the burn, the bar feels heavy, and they rack it thinking "that was a 1 or 2 RIR set" when video would show a fast, controlled bar with four reps to spare. The internal sensation of effort outruns the actual mechanical proximity to failure. This is exactly the gap Riven was built to close: it reads rep-speed decay off your Apple Watch and turns it into an objective 0–100 failure-proximity score, so you get a number instead of a guess about whether the set was real.

Junk volume vs effective reps

To understand why easy sets are junk, you have to understand effective reps — sometimes called stimulating reps. Not every rep in a set grows muscle. Chris Beardsley's stimulating-reps model estimates only about 5 stimulating reps per set taken to failure (likely toward the low end of a 5–8 range). Those are the final reps where two things finally coincide: full motor unit recruitment and a slow bar.

Both conditions matter, and this is the part most articles botch. Full motor unit recruitment kicks in around 80–88% of 1RM, roughly a 5RM load — or, at lighter loads, only once you've fatigued into the back half of a set. But recruitment alone doesn't grow muscle. The fiber also has to shorten slowly. By the force-velocity relationship, a slow rep produces high mechanical tension per fiber; a fast, explosive rep recruits everything but produces low single-fiber tension because it's moving too quickly. That's why a snappy speed-bench rep doesn't build the same muscle as a grinding final rep — and why leaving six reps in the tank is biomechanically junk, not just psychologically lazy. The high-tension reps simply never happen.

So effective reps and the volume debate aren't in conflict — they're the same coin. A "hard set" counts as one unit of productive volume precisely because it delivers ~5 stimulating reps. An easy set delivers near zero. That's junk volume in one sentence: you pay the set cost without collecting the stimulating reps.

This reframes the whole "high volume vs low volume" argument. Three sets to failure (~28 total reps) and four sets of seven near failure (~28 reps) can grow similar muscle because the stimulating-rep totals end up comparable. The trap is doing four easy sets that never reach the stimulating zone — full volume cost, almost no benefit.

Is more volume always better? (the diminishing returns curve)

No. More volume helps — up to a point — then flattens, then turns negative. The landmark dose-response meta-analysis from Schoenfeld, Ogborn & Krieger (2017) found a graded relationship: each added weekly set per muscle bumped effect size by ~0.023 (about 0.37% extra muscle per set), and 10+ weekly sets beat 5–9, which beat fewer than 5. Volume matters. But notice the magnitude — that's a small, diminishing return per set, not a linear ramp you can ride forever.

The clearest picture of where the curve flattens comes from proximity-to-failure data. The Refalo et al. (2022) meta-analysis found no significant advantage to training to momentary failure over non-failure when volume was equated (ES = 0.12, 95% CI −0.13 to 0.37, p = 0.343). Translation: you don't have to hit failure. But the same review's velocity-loss analysis shows you do have to get close:

Look at where the jump is. Going from "easy" to "moderately hard" nearly doubles the effect (0.20 → 0.39). Grinding from moderately hard all the way to absolute failure barely moves it (0.39 → 0.42). The curve isn't a cliff — it's a steep climb that levels off around 20% velocity loss. The cheapest fix for junk volume is pushing easy sets to roughly 2 reps from failure — not adding sets, and not chasing maximal failure.

And it does invert eventually. Robinson et al. (2024) found hypertrophy rises as sets get closer to failure — but every hard set drains recovery. Nippard pegs the benefit as clear up to about 6 sets per session and counterproductive beyond ~6–8. Per muscle per week, 10–20 hard sets is the productive window for most people, though it's not flat across the body — bigger muscles like back, glutes, and quads tolerate more (10–12+), while smaller muscles top out around 6–8. A blanket "do 20 sets for everything" prescription manufactures junk volume on the muscles that max out earlier.

One more trap worth naming: ultra-high-rep light sets. Training below ~20% 1RM for 40–50+ reps produces soreness and a brutal pump out of proportion to the actual growth. The burn feels productive. It mostly isn't.

How to make every set count

Stop counting sets. Start counting hard sets near failure — that's the currency Greg Nuckols argues for, and it's right. Total volume load (sets × reps × weight) can't tell a near-failure set from an easy one, so it's a lousy proxy for stimulus. Here's how I get clients out of junk volume:

1. Take most working sets to 0–3 reps from failure. This is the practical consensus across Nippard, Henselmans, and Nuckols. You don't need to grind to failure on everything — Refalo's 2024 RCT in trained lifters found near-identical quad growth training to failure versus 1–2 RIR (+0.181 cm vs +0.182 cm quadriceps thickness), and the RIR group recovered better. Train hard, not maximal.

1. Fix intensity before adding volume. If your sets are easy, the answer is fewer, harder sets — not more easy ones. Cheapest possible upgrade: take your current program and just push every set two reps deeper.

1. Don't autoregulate by strength alone. Robinson found proximity to failure barely affects strength gains but strongly affects hypertrophy. So a lifter who judges effort by "did I add weight to the bar?" can keep getting stronger on the same junk sets while leaving size on the table.

1. Get an objective read on effort. This is the hard one, because RIR estimation is genuinely unreliable. Content sites give you subjective cues — shaking, burning, grimacing. Rep-counting apps count reps but say nothing about whether you actually fought for them. Riven measures velocity loss from your Apple Watch — no camera, no barbell clip — and tells you per muscle group how close each set got to true failure. Be straight about what it is: the wrist signal is a proxy for barbell velocity loss, reading roughly half the magnitude of a $300 linear position transducer at equal fatigue. It's not lab-grade or EMG. But it's an objective number where you currently have a guess — and for separating a stimulating set from a junk one, that beats feel every time.

The whole game is concentration of effort. A leaner program of genuinely hard sets will out-grow a sprawling one full of easy ones, and it'll cost you less recovery. Make the sets count, and you can do fewer of them.

FAQ

What is junk volume in lifting?

Junk volume is training volume — sets and reps — that doesn't add muscle or strength because the sets are too far from failure, too light, or so excessive they hurt recovery. The most common form is easy sets stopped 5+ reps shy of failure.

How do I know if a set is junk volume?

If you could have done 4–5 more clean reps, the load was trivial, or the set was so deep it tanks your next session, it's likely junk. Because lifters overestimate effort, an objective velocity-loss read (like Riven's) is more reliable than feel.

Is more volume always better for muscle growth?

No. Volume helps with diminishing returns and eventually turns negative — beyond roughly 6–8 hard sets per session (10–20 per muscle per week for most), extra sets add fatigue without added stimulus.

Do I have to train to failure to avoid junk volume?

No. Volume-equated research (Refalo) shows 1–3 reps from failure grows muscle as well as failure and recovers better. The set counts if it's hard, not if it's maximal.

Why don't all my reps build muscle?

Only the final ~5 stimulating reps — where full motor unit recruitment and slow bar speed coincide — drive most growth. Early easy reps mainly accumulate fatigue.

Sources

• Schoenfeld, Ogborn & Krieger (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass. Journal of Sports Sciences. PDF
• Robinson, Pelland, Remmert, Refalo, Jukic, Steele & Zourdos (2024). Exploring the Dose–Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy. Sports Medicine. Link
• Refalo, Helms, Trexler, Hamilton & Fyfe (2022). Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis. Sports Medicine. PMC9935748
• Refalo et al. (2024). Similar muscle hypertrophy following eight weeks of resistance training to momentary muscular failure or with repetitions-in-reserve. Journal of Sports Sciences. PubMed
• Beardsley, C. How many stimulating reps are there in each set to failure? S&C Research
• Nippard, J. Junk Volume: Why You Must Avoid It For Max Muscle. jeffnippard.com
• Nuckols, G. More is More. Stronger By Science